The present invention relates to outdoor signs, and in particular to mobile electronically changeable signs for use adjacent to roadways.
Highway warning signs are frequently needed to warn motorists of obstructions, traffic delays, and hazardous conditions as such conditions arise. To be most useful, a highway warning sign should be mobile so that the sign may be transported to the needed site. Once the sign has been moved to the needed site, the sign may be left along the roadway to warn passing motorists. Generally, the sign must be readable from at least 150 feet and often from much farther away.
In order to be visible in a variety of lighting conditions (bright sunlight, overcast, nighttime, etc.) the sign""s warning should be illuminated, i.e., the sign elements should be electrically powered. The sign elements may be light emitting diodes (LEDs) or dot sign units which flip over and are alternatively illuminated when flipped over in order to spell out a message on the sign.
The environment such signs are used in are highly deleterious to electrical and mechanical mechanisms due to moisture, salt, dirt, debris, temperature variations, wind, ice, etc. Thus, such signs need to be resistant to these elements. Moreover, such signs need to be easily cleaned to remove these elements, particularly where they may obstruct the visibility or readability of the sign.
Because electrical power may not be available at the sit of the hazard or obstruction, the sign should operate off batteries. However, the batteries should also be rechargeable from solar energy because of the limited charge lifetime of any battery. Therefore, the sign should have a solar panel for recharging the batteries.
There is a need for a mobile sign with a solar panel which can be adjusted to the position of the sun without moving the trailer, in order to maximize the ability of the solar panel to charge the batteries.
A mobile highway sign must also have a display that is highly visible under a variety of lighting conditions. Reflected glare from the sun or other external light sources should be minimized while the contrast of the sign""s display should be maximized. There is a need for a mobile sign with a display that minimizes reflected glare and at the same time maximizes the contrast of the display.
Heat from the sun may reduce the life of electronic components of the sign and of display elements such as light-emitting diodes (LED). There is a need for a sign with a display which reduces the amount of heat from the sun entering the display.
A preferred embodiment of the present invention is a mobile sign with a solar panel for warning motorists of highway problems. The mobile sign comprises support structure configured as a wheeled vehicle. In preferred embodiments, the sign panel comprises an enclosure or housing having a front transparent panel, a multiplicity of LED""s in a matrixical arrangement for generating electronically changeable messages mounted in the enclosure and spaced from the front panel, and a pattern of opaque material, for example paint, applied on the exterior of the front transparent panel defining a plurality of windows for passing light therethrough.
In a preferred embodiment, the windows will be in a matrixical arrangement comprising a plurality of rows and columns of individual LED""s or rows and columns of groupings of LEDs, such that individual LED""s or a grouping or cluster of LED""s are associated with a specific window. A specific window may thus have one or more LED""s. The light pattern from each LED will be cast through its respective window to be visible to the intended view, such as a passing motorist.
A principal object and advantage of the invention is that the sign panel has a low-glare, high-contrast display that also improves the lifetime of the display""s electronic or mechanical components by reducing heating of the display due to the sun. Moreover, the messages displayed are more readable due to low glare-high contrast front panel.
A further object and advantage of the invention is that the opaque material is preferably applied as a liquid material, for example a paint, onto the outside surface of the transparent front panel and is allowed to cure or dry whereby a layer that is sealed to transparent front face is provided, precluding entry of moisture, debris, or other contaminants between the opaque layer and the front face of the front panel. Such application provides a durable, lightweight, easy to manufacture and inexpensive opaque layer with a continuous bonding between the opaque layer and the front panel surface.
A feature and advantage of the invention is that use of paint to create the opaque zones creates a surface highly amenable to cleaning and resistant to the elements associated with roadside usage. For example, the transition between the transparent window and the opaque areas is generally a smooth transition with paint and provides a thickness of, for example, 0.45 mm to 2.0 mm. Such a smooth transition and minimal thickness of the opaque layer as well as the continuous bonding between the opaque layer and the surface of the transparent panel facilitates cleaning and provides the resistance to the elements.
A principal object and advantage of certain embodiments of the invention is that the sign has a solar panel which is tiltable and rotatable relative to the frame of the wheeled vehicle, thus making it easy to change the angle of the solar panel relative to the sun. The most electricity is generated from a solar panel when the sun""s rays are perpendicular to the face of the solar panel. Accordingly, the sign has a solar panel which is tiltable and rotatable relative to the sign and to the wheeled vehicle in order to position the solar panel so that the sun""s rays are most nearly perpendicular to it. The optimum position will vary from hour to hour, day to day, and month to month. The sign may be left at the site for a few hours or a few weeks or several months. The position of the solar panel is easily adjustable at whatever frequency makes sense.
Another object and advantage of certain embodiments of the present invention is that the position of the solar panel may be adjusted without moving the wheeled vehicle, thereby accommodating situations where the wheeled vehicle cannot be moved because of the presence of other nearby objects.
Another object and advantage of certain embodiments of the present invention is that the solar panel is mounted on a mast so that it may be elevated above the sign panel, thereby preventing the sign panel from blocking the sun.
Another object and advantage of certain embodiments of the present invention is that the tilting and rotation of the solar panel is accomplished by controls at the level of the standing human operator, thereby making it easy to position the solar panel above the sign panel without a ladder.
Another object and advantage of certain embodiments of the present invention is that the solar panel tilts to a completely horizontal position for transport, thus minimizing wind resistance.
Another object and advantage of certain embodiments of the invention is that the front face of the display may be tiled so as to minimize reflected glare from the sun and to make the display self-shading.